[PATCH 2/3] TI QSPI: add support for dual and quad-bit I/O read

Jean Pihet jean.pihet at newoldbits.com
Sun Nov 29 11:39:47 CET 2020


TI QSPI: the TI QSPI IP has a limitation of 64MB of MMIO so use
the MMIO mode to read below 64MB and fallback to the SW generated
sequences to read above 64MB.
The TI QSPI IP has another limitation of 4096 words per frame,
so split the accesses into smaller ones.
Also fix the TI QSPI operating frequency in order to correctly
generate the required SPI CLK frequency.

Signed-off-by: Jean Pihet <jean.pihet at newoldbits.com>
---
 drivers/spi/Kconfig   |  9 ++++++
 drivers/spi/ti_qspi.c | 68 ++++++++++++++++++++++++++++++++++++-------
 2 files changed, 66 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index f7a9852565..5d24029ff0 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -395,10 +395,19 @@ config TEGRA210_QSPI
 config TI_QSPI
 	bool "TI QSPI driver"
 	imply TI_EDMA3
+	imply TI_QSPI_MQX_FRAME_SIZE
 	help
 	  Enable the TI Quad-SPI (QSPI) driver for DRA7xx and AM43xx evms.
 	  This driver support spi flash single, quad and memory reads.
 
+config TI_QSPI_MAX_FRAME_SIZE
+	int "TI QSPI max frame size"
+	default 4096
+	help
+	  TI Quad-SPI (QSPI) IP block has a maximum number of 4096 words in a
+	  frame, in non-memory mapped mode. A frame includes the command,
+	  arguments and dummy bytes.
+
 config UNIPHIER_SPI
 	bool "Socionext UniPhier SPI driver"
 	depends on ARCH_UNIPHIER
diff --git a/drivers/spi/ti_qspi.c b/drivers/spi/ti_qspi.c
index 5fdbb49442..57192b9c0a 100644
--- a/drivers/spi/ti_qspi.c
+++ b/drivers/spi/ti_qspi.c
@@ -29,7 +29,7 @@ DECLARE_GLOBAL_DATA_PTR;
 
 /* ti qpsi register bit masks */
 #define QSPI_TIMEOUT                    2000000
-#define QSPI_FCLK			192000000
+#define QSPI_FCLK                       48000000
 #define QSPI_DRA7XX_FCLK                76800000
 #define QSPI_WLEN_MAX_BITS		128
 #define QSPI_WLEN_MAX_BYTES		(QSPI_WLEN_MAX_BITS >> 3)
@@ -41,10 +41,11 @@ DECLARE_GLOBAL_DATA_PTR;
 #define QSPI_EN_CS(n)                   (n << 28)
 #define QSPI_WLEN(n)                    ((n-1) << 19)
 #define QSPI_3_PIN                      BIT(18)
-#define QSPI_RD_SNGL                    BIT(16)
+#define QSPI_RD_SNGL                    (1 << 16)
+#define QSPI_RD_DUAL                    (3 << 16)
+#define QSPI_RD_QUAD                    (7 << 16)
 #define QSPI_WR_SNGL                    (2 << 16)
 #define QSPI_INVAL                      (4 << 16)
-#define QSPI_RD_QUAD                    (7 << 16)
 /* device control */
 #define QSPI_CKPHA(n)                   (1 << (2 + n*8))
 #define QSPI_CSPOL(n)                   (1 << (1 + n*8))
@@ -155,6 +156,7 @@ static int ti_qspi_xfer(struct udevice *dev, unsigned int bitlen,
 			const void *dout, void *din, unsigned long flags)
 {
 	struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
+	struct spi_slave *spi_slave = dev_get_parent_priv(dev);
 	struct ti_qspi_priv *priv;
 	struct udevice *bus;
 	uint words = bitlen >> 3; /* fixed 8-bit word length */
@@ -182,7 +184,6 @@ static int ti_qspi_xfer(struct udevice *dev, unsigned int bitlen,
 
 	/* Setup command reg */
 	priv->cmd = 0;
-	priv->cmd |= QSPI_WLEN(8);
 	priv->cmd |= QSPI_EN_CS(cs);
 	if (priv->mode & SPI_3WIRE)
 		priv->cmd |= QSPI_3_PIN;
@@ -206,15 +207,16 @@ static int ti_qspi_xfer(struct udevice *dev, unsigned int bitlen,
 				writel(data, &priv->base->data1);
 				data = cpu_to_be32(*txbuf++);
 				writel(data, &priv->base->data);
-				cmd &= ~QSPI_WLEN_MASK;
 				cmd |= QSPI_WLEN(QSPI_WLEN_MAX_BITS);
 				xfer_len = QSPI_WLEN_MAX_BYTES;
 			} else {
 				writeb(*txp, &priv->base->data);
+				cmd |= QSPI_WLEN(8);
 				xfer_len = 1;
 			}
 			debug("tx cmd %08x dc %08x\n",
 			      cmd | QSPI_WR_SNGL, priv->dc);
+			// Only 1-bit write is supported
 			writel(cmd | QSPI_WR_SNGL, &priv->base->cmd);
 			status = readl(&priv->base->status);
 			timeout = QSPI_TIMEOUT;
@@ -229,9 +231,17 @@ static int ti_qspi_xfer(struct udevice *dev, unsigned int bitlen,
 			debug("tx done, status %08x\n", status);
 		}
 		if (rxp) {
+			u32 rx;
+			/* Check for dual and quad reads */
+			u32 readcmd_cmd = QSPI_RD_SNGL | QSPI_WLEN(8);
+			if (spi_slave->flags & SPI_XFER_DUAL_READ)
+				readcmd_cmd = QSPI_RD_DUAL | QSPI_WLEN(16);
+			if (spi_slave->flags & SPI_XFER_QUAD_READ)
+				readcmd_cmd = QSPI_RD_QUAD | QSPI_WLEN(32);
+
 			debug("rx cmd %08x dc %08x\n",
-			      ((u32)(priv->cmd | QSPI_RD_SNGL)), priv->dc);
-			writel(priv->cmd | QSPI_RD_SNGL, &priv->base->cmd);
+			      ((u32)(priv->cmd | readcmd_cmd)), priv->dc);
+			writel(priv->cmd | readcmd_cmd, &priv->base->cmd);
 			status = readl(&priv->base->status);
 			timeout = QSPI_TIMEOUT;
 			while ((status & QSPI_WC_BUSY) != QSPI_XFER_DONE) {
@@ -241,10 +251,28 @@ static int ti_qspi_xfer(struct udevice *dev, unsigned int bitlen,
 				}
 				status = readl(&priv->base->status);
 			}
-			*rxp++ = readl(&priv->base->data);
-			xfer_len = 1;
-			debug("rx done, status %08x, read %02x\n",
-			      status, *(rxp-1));
+			rx = readl(&priv->base->data);
+			if (spi_slave->flags & SPI_XFER_QUAD_READ) {
+				if (words >= 1)
+					*rxp++ = rx >> 24;
+				if (words >= 2)
+					*rxp++ = rx >> 16;
+				if (words >= 3)
+					*rxp++ = rx >> 8;
+				if (words >= 4)
+					*rxp++ = rx;
+				xfer_len = (words >= 4) ? 4 : words;
+			} else if (spi_slave->flags & SPI_XFER_DUAL_READ) {
+				if (words >= 1)
+					*rxp++ = rx >> 8;
+				if (words >= 2)
+					*rxp++ = rx;
+				xfer_len = (words >= 2) ? 2 : words;
+			} else {
+				*rxp++ = rx;
+				xfer_len = 1;
+			}
+			debug("rx done, status %08x, rx=%08x\n", status, rx);
 		}
 		words -= xfer_len;
 	}
@@ -353,6 +381,23 @@ static int ti_qspi_exec_mem_op(struct spi_slave *slave,
 	return ret;
 }
 
+static int ti_qspi_adjust_size(struct spi_slave *slave, struct spi_mem_op *op)
+{
+#ifdef CONFIG_TI_QSPI_MAX_FRAME_SIZE
+	// Adjust the data length to fit in the QSPI max frame length
+	if (op->data.dir == SPI_MEM_DATA_IN) {
+		unsigned int data_len = CONFIG_TI_QSPI_MAX_FRAME_SIZE -
+								sizeof(op->cmd.opcode) - op->addr.nbytes -
+								op->dummy.nbytes;
+		// Align the data on cache line
+		data_len = data_len & ~(ARCH_DMA_MINALIGN - 1);
+		op->data.nbytes = min(op->data.nbytes, data_len);
+	}
+#endif
+
+	return 0;
+}
+
 static int ti_qspi_claim_bus(struct udevice *dev)
 {
 	struct dm_spi_slave_platdata *slave_plat = dev_get_parent_platdata(dev);
@@ -482,6 +527,7 @@ static int ti_qspi_ofdata_to_platdata(struct udevice *bus)
 
 static const struct spi_controller_mem_ops ti_qspi_mem_ops = {
 	.exec_op = ti_qspi_exec_mem_op,
+	.adjust_op_size = ti_qspi_adjust_size,
 };
 
 static const struct dm_spi_ops ti_qspi_ops = {
-- 
2.26.2



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